The aim of the article is to demonstrate how the KLEMS economic productivity accounts for Poland have been performed. The main research problem was to find solutions to certain country‑specific data insufficiencies. On this basis, a hypothesis was put forward that by using some innovative but acceptable missing data assessment techniques, it is possible to supply sufficient data for Poland for the mentioned accounts. After an overview of KLEMS economic productivity accounts and the relevant fundamental methodology, the article presents further how specific data problems that have arisen have been solved.  

The aim of the article is to present the main body of the KLEMS growth accounting recently implemented in Poland. The works on the KLEMS productivity accounting in Poland started in 2013 and focused on areas such as the development of methodology and the availability and assessment of data. These efforts enabled preparing KLEMS data sets pertaining to the Polish economy and moreover proved that unavailable data can be effectively estimated. Additionally, interesting but complex and debatable results were obtained, such as labour hoarding together with remunerations' freezing around the 2009 crisis, accompanied by a natural drop in the capital contribution growth and an increase in the MFP contribution, which most probably indicated effective reorganizations in the economy. In the years 2012−2014, increasing labour and capital contributions did not fully translate into gross value added growth, which led to negative MFP growths, as these are calculated residually. This, however, changed completely in the last two years of the time span covered by the research, namely in 2015-2016. An industry-level analysis became also possible, showing that the Polish economy was developing dynamically and undergoing intensive modernisation, which was obtained, however, with a debatable contribution of the State. To study the debatable features of the Polish economy in a greater detail, a further decomposition of the labour factor growth into four sub-factor contributions instead of two sub-factor contributions was performed. This additional analysis confirmed that labour hoarding phenomenon specific for Poland contributed to a softer impact of the 2007−09 financial crisis on this country's economy.

The article presents the origins of the KLEMS Growth and Productivity Accounts, that is descendant from the Solow’s well known economic growth decomposition. They discuss further the methodological details of the Accounts, present the international context and the implementation aspects of the KLEMS Growth and Productivity Accounts in Poland, that is actually being performed in the Central Statistical Office of Poland (CSO). They focus on the specific data environment for this productivity accounts in Poland. Specific techniques of data pre-calculation are presented for the two primary factors — labour and capital.

The mode of wages and salaries is an important indicator describing their distribution; however, due to the strong asymmetry of the distribution of this feature in Poland, mode estimation is not a standard procedure in the analysis of the structure of wages and salaries. The aim of the article is to discuss selected methods of estimating the mode and to compare the mode estimation results obtained by means of various methods. The research is based on data on individual gross wages and salaries registered in October 2018 in Poland. The data came from a survey of the structure of wages and salaries conducted by Statistics Poland. In the case of the standard method based on the interpolation formula and histogram, the mode estimate is sensitive to the assumed span of intervals in the frequency table and the beginning of the first interval. Reducing the span of the intervals causes the mode to reach the value of the minimum wage. The application of advanced methods, including those using a kernel estimator, leads to significantly different estimates of the mode depending on the method used (the dispersion reaches the value of approximately PLN 800). Additionally, the analysis of the obtained results gives grounds to considering a thesis that wage and salary distribution is a mixture of the following distributions: discrete (for the minimum wage) and continuous (for wages and salaries above the minimum wage), and is characterised by cyclicality (in Poland, more contracts offer remunerations which are a multiple of PLN 50 or PLN 100 than remunerations for other amounts).

There is an ongoing discussion that many middle-income countries are on the brink of the so-called Middle-income Trap, if not already stuck in it. The case of the Polish economy is analyzed, as an example of a Central-Eastern Europe economy, to solve whether this is actually happening. Thanks to KLEMS growth accounting datasets published by Statistics Poland an analysis on this issue became feasible, showing that for Poland the assertion of the middle-income trap threat has to be rejected after observing the growth distribution between industries, and particularly their growth decompositions into factor and MFP contributions. Extending this research to some other countries may possibly confirm that, just as for Poland, this "trap" is not taking place (or the converse). Although not solving the theoretical nexus on the middle-income trap notion, these findings can be interesting for Central-Eastern Europe economies' researchers and the possible ongoing discussion.